Middle Jurassic strata link Wallowa, Olds Ferry, and Izee terranes in the accreted Blue Mountains island arc, northeastern Oregon

Journal Article · Sat Aug 01 00:00:00 EDT 1992 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1992)020<0729:MJSLWO>2.3.CO;2· OSTI ID:6991697

White, J D.L. ^[1]; Vallier, T ^[2]; Stanley, Jr, G D ^[3]; Ash, S R ^[4]; White, D L

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1. Dalhousie Univ., Halifax, Nova Scotia (Canada)
2. Geological Survey, Menlo Park, CA (United States)
3. Univ. of Montana, Missoula (United States)
4. Weber State Univ., Odgen, UT (United States)

Middle Jurassic strata atop the Wallowa terrane in northeastern Oregon link the Wallowa, Izee, and Olds Ferry terranes as related elements of a single long-lived and complex oceanic feature, the Blue Mountains island arc. Middle Jurassic strata in the Wallowa terrane include a dacitic ash-flow deposit and contain fossil corals and bivalves of North American affinity. Plant fossils in fluvial sandstones support a Jurassic age and indicate a seasonal temperate climate. Corals in a transgressive sequence traditionally overlying the fluvial units are of Bajocian age and are closely related to endemic varieties of the Western Interior embayment. They are unlike Middle Jurassic corals in other Cordilleran terranes; their presence suggests that the Blue Mountains island arc first approached the North American craton at high paleolatitudes in Middle Jurassic time. The authors consider the Bajocian marine strata and underlying fluvial volcaniclastic units to be a basin-margin equivalent of the Izee terrane, a largely Middle Jurassic (Bajocian) succession of basinal volcaniclastic and volcanic rocks known to overlie the Olds Ferry and Baker terranes.

• OSTI ID: 6991697
• Journal Information: Geology; (United States), Vol. 20:8; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
OREGON
SEDIMENTARY BASINS
PALEONTOLOGY
STRATIGRAPHY
AGE ESTIMATION
COMPARATIVE EVALUATIONS
CORALS
CORRELATIONS
GEOLOGIC HISTORY
GEOLOGIC STRATA
JURASSIC PERIOD
MOLLUSCS
PALEOCLIMATOLOGY
SUBDUCTION ZONES
VOLCANIC ROCKS
ANIMALS
AQUATIC ORGANISMS
CNIDARIA
COELENTERATA
DEVELOPED COUNTRIES
EVALUATION
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
INVERTEBRATES
MESOZOIC ERA
NORTH AMERICA
ROCKS
USA
580000* - Geosciences